/*
* JBoss, Home of Professional Open Source.
* Copyright 2006, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.aspects.concurrent;
import org.jboss.aop.joinpoint.Invocation;
import java.util.concurrent.Semaphore;
/**
* comment
*
* @author <a href="mailto:bill@jboss.org">Bill Burke</a>
*/
public class SemaphoredMethodAspect
{
protected Semaphore semaphore;
protected SemaphoredMethod props;
public SemaphoredMethodAspect(SemaphoredMethod m)
{
props = m;
semaphore = new Semaphore(m.permits(), m.isFair());
}
public Object acquire(Invocation invocation) throws Throwable
{
if (props.timeout() == -1)
{
blockIndefinately();
}
else if (props.timeout() == 0)
{
tryLock();
}
else
{
tryLockWithTimeout();
}
try
{
return invocation.invokeNext();
}
finally
{
semaphore.release();
}
}
protected void blockIndefinately()
{
try
{
semaphore.acquire();
}
catch (InterruptedException e)
{
throw new LockAcquisitionFailureException("Failed to acquire permit for @SemaphoredMethod", e);
}
}
protected void tryLock()
{
if (!semaphore.tryAcquire())
{
throw new LockAcquisitionFailureException("Failed to acquire permit for @SemaphoredMethod");
}
}
protected void tryLockWithTimeout()
{
try
{
if (!semaphore.tryAcquire(props.permits(), props.timeout(), props.unit()))
{
throw new LockAcquisitionFailureException("Failed to acquire permit for @SemaphoredMethod. Timeout reached.");
}
}
catch (InterruptedException e)
{
throw new LockAcquisitionFailureException("Failed to acquire permit for @Semaphored class", e);
}
}
}
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